Precision stripper blade

ABSTRACT

A stripper blade for use in removing the insulation from one end of an insulated wire and having a cutting knife mounted in an integrally molded supporting structure; the cutting knife has a cutting edge formed with a plurality of notches. A method of fabricating stripper blades having the steps of forming a cutting knife, inserting the cutting knife in a mold cavity, inserting mold material into the mold cavity, solidifying the mold material, and ejecting the molded stripper blade from the mold cavity. A mold for use in fabricating stripper blades and having a mold bottom, a mold cover and removable knockout pins adapted to close in registry to form a mold cavity having the contour of the desired molded stripper blade; one removable knockout pin contains molding means and a groove adapted to receive a cutting knife and align the cutting knife in cooperation with registry and alignment pins formed in the mold cover and bottom.

United States Patent FOREIGN PATENTS 00 6 w .m a .H r B t a e r G m 9 1l 9 7 5 7 8 21 AppLNo. 854,352 22 Filed Primary ExaminerLester M.Swingle Aug. 15,1969 [451 Patented Sept. 14,1971

Assistant Examiner-J. C. Peters; Attorney-Parker, Carter & MarlteyABSTRACT: A stripper blade for use in removin [73] Assignee IdealIndustries, Inc.

Sycamore, Ill. Continuation-impart of application Ser. No.

g the insulafrom one end of an insulated wire and having a cuttinggrally molded supporting structure;

tting edge formed with a plurality of notches.

7 m A W L n.n W2 R mmm mm :1. P 26% mm. ""m Tw mmmw Sr "mh ND m m ommmw. fls mmS6 1 m han Eh W d RC SLM P3 UhF m mwm contour of the desiredmolded stripper blade: one removable f 0: SC m m mm mm e Win a 3U. e homi k tefm nM m n n." .mm skv v e 3 306 dkc mm mwm fiflOO [V0 dwmm e m t.e e 6 Wm a h mh r uto... m g S W.m.m.m m m m w ma Sf Bn q .w w i ot l cste,md m mb w m e .lnd IT. I I. no b lfin mn a ma :l 2. i n r e i eCU Sonnt i0 m mmd MC m f m md mw m nmm bw miwm m t A A w ah d hctfi ma Ms mm l 9 SMM 2 B [56] References Cited UNITED STATES PATENTS 10/1964Gormley....................... 10/1966 Craig knockout pin containsmolding means and a groove adapted to receive a cutting knife and alignthe cutting knife in cooperation with registry and alignment pins formedin the mold cover and bottom. 1

PRECISION STRIPPER BLADE This application is a continuation-in-part ofmy copending application Ser. No. 622,546, filed Mar. 13, 1967, nowabandoned, which was a continuation-in-part of my copending applicationSer. No. 584,399, filed Oct. 5, 1966, and now U.S. Pat. No. 3,416,227

SUMMARY OF THE INVENTION This invention is in the field of wirestrippers and is primarily concerned with a stripper blade for use in ahand-operated stripper, although it should be understood that most, ifnot all, of the features of this invention could be used as well inother types of strippers, for example bench-mounted strippers and/orpower-operated units and the like.

In stripping insulation from insulated wire which is to be used inelectronic equipment in the defense and other industries requiringhighly reliable equipment, it is essential that the insulation bestripped from such wire without nicking and thereby weakening such wiresinner metallic conductor. In fabricating stripper blades for use in handor power-operated strippers, it is desirable to have a process wherebycostly machining operations in forming the wire-stripping areas of theblade are eliminated and whereby stripper blades may be fabricatedindividually and not as matched pairs. Further, it is highly desirableto have an economical method of fabricating precision stripper bladesfor use in stripping special wire forms, such as television antenna wireand the like.

Therefore, one object of this invention is a highly precise and accuratestripper blade for either hand or power-operated strippers which willstrip insulation from wire without nicking the inner metallic conductor.

Another object is a stripper blade which may be molded out of plastic orother suitable material.

Another object is a stripper blade which insures accurate lateralcentering of the cutting edge of such blade about the wire which is tobe stripped.

Another object is a stripper blade which may be fabricated using aninjection molding machine.

Another object is a stripper blade having a cutting edge consisting of athin metal insert.

Another object is a stripper blade having a cutting edge which does notrequire sharpening.

Another object is a method of molding precision stripper blades.

Another object is a method of fabricating stripper blades which resultsin a uniform, interchangeable-end product.

Another object is an economical method which facilitates the productionof special stripper blades for stripping insulation from special wireshapes such as television antenna wire and the like.

Another object is a mold for producing stripper blades which facilitatesfabrication of variously configured stripper blades.

Another object is a mold, for use in fabricating stripper blades, havingmultiple collet mold inserts which allows the use of the same mold inproducing stripper blades, respectively having different wire size andform-stripping capabilities.

Another object is a stripper blade formed using plastic or otherself-lubricating material to eliminate lubrication problems between themoving blade and the wire stripper mounting frame.

Another object is an economical method of manufacturing stripper bladeshaving cutting means which would be extremely difficult and expensive toproduce by machining.

Another object is a stripper blade and a method of manufacture whichpermits the economical use of a carbide cutting edge.

Other objects will appear in the ensuing specification, drawings andclaims.

Brief Description of the Drawings FIG. 1 is a plan view in partial crosssection of a hand-type wire stripper utilizing an exemplary pair ofstripper blades of 7 tion; and

FIG. 5 is a cross-sectional view showing a completed exemplary stripperblade being ejected from the mold of FIG. 4 after such mold parts haveseparated.

Description of the Preferred Embodiment Referring now to the drawings,and particularly to FIG. 1, stripper blades 42 and 44 are shown mountedin a hand stripper of the type generally illustrated in U.S. Pat. No.2,523,936 issued Sept. 26, 1950. It should be understood, however, thatthe stripper blade of this invention may also be used in benchstrippers, such as shown in U.S. Pat." No. 2,239,755 issued Apr, 29,1941, or other like devices for use in stripping insulation from wire.For details of the particular strippers mentioned, reference is made tothe above patents. Generally, however, a wire stripper utilizing thestripper blades 42 and 44 includes a pair of body members or arms 10 and12, pivoted together at 14, with such pivot also functioning as thepivot for a pair of legs or handles 16 and 18. The handles 16 and 18 arespring-biased apart by a suitable coil spring 24 or the like. A suitablecoil spring, not shown, is provided in a housing 26 on the back pivot14, each end of which is anchored into one of the arms 10 and 12 to biassuch arms together at all times. A suitable latch 28, either between thearms or otherwise to initially resist or restrain the return movement ofthe arms 10 and 12, is provided to allow jaws 30 and 32 to open so thatthe wire can be removed after such wire has been stripped. For detailsof the latch operation, reference is made to U.S. Pat. No. 2,523,936.

The clamping jaws 30 and 32 are mounted in one arm 10, with the lowerjaw 30 being stationary and the upper jaw 32 being movable in theup-down direction. To provide such movement, a link 34 is pivoted on oneend of the handle 16 and at its other end on a pending tail 36 of thejaw 32. The opposed faces 38 and 40 of the clamping jaws grip and holdbetween them the outer insulation of the wire to be stripped. On theother arm 12, the stripper blades 42 and 44 are mounted, with the bottomblade 42 stationary and the top blade 44 being movable in the up-downdirection. To provide such movement, a link 34 is pivoted on one end ofthe handle 18 and at its other end on a pending tail 36' of the stripperblade 44. The jaws 30 and 32 and the blades 42 and 44 are suitably heldin place by retained plates, such as at 48.

With reference now to FIGS. 2 and 3, an exemplary operative set ofstripper blades 42 and 44 of this invention have been shown ascomprising a molded structure having a thin metal insert or cuttingknife 60 and 60' respectively molded therein. The stripper blades 42 and44 are shown configured for use in the hand stripper of FIG. 1, with thelower blade 42 being generally L-shaped and having two mounting holes61, while the movable upper stripper blade 44 has been shown as beinggenerally C-shaped. It should be understood, however, that the stripperblade of this invention is not limited to the shapes shown and may be ofany general shape depending upon the requirements of the stripper withwhich such blade is to operate.

The cutting knives 60 and 60 contain notches or semicircular holes 64and 64 respectively in the edges thereof. The diameter of the knife edgenotch 64 or 64 is slightly larger than the diameter of the innermetallic conductor of the wire to be stripped. Associated with eachknife edge notch is a collet, such as at 66, which is generally sizedand configured to conform to the size and configuration of theinsulation of the wire to be Stripped. Although the collets have beenshown as being generally circular, it should be understood that suchcollets may be molded to conform to specially configured wire, such astelevision antenna wire and the like. Further, although each blade isshown as having four sets of notches and collets, it should beunderstood that each stripper blade may have more or less than four setsof notches and collets. Further, although a stripper blade havingcollets and a notched, unsharpened metal insert has been depicted andhas and will be described, it should be understood that this inventionis not limited to such exemplary form. For example, the stripper bladeof this invention may be colletless and the metal insert may be of anypractical size and may have a sharpened single or double bevel cuttingedge of a compound shape containing centering and/or locating bosses andnotches.

In FIG. 4, an exemplary two-part mold with which the stripper blade ofthis invention may be molded has been shown. The numeral 70 indicatedone-half of the mold which will be hereinafter referred to as the moldbottom. The numeral 72 indicates the mold cover. The mold bottom andcover contain recessed and extending areas such that when the moldbottom and cover are locked together, a cavity or chamber 74 is formedwhich conforms to the outlines of the finished stripper blade. The thinmetal insert or cutting knife 60 is shown within the cavity 74 with suchcutting knife being positioned laterally and vertically by the moldinsert centering pins 76 and mold insert registry pins 78 respectively.The cutting knife is shown resting on and partially inserted in aremovable collet mold insert and knockout pin 80. The collet mold insertand knockout pin 80 contains a plurality of collet molds 84, each ofwhich has an outside contour conforming to the inside contour of thedesired molded collet 66 of the finished stripper blade. Each colletmold 84 contains a peripheral groove 85 having a minor diameterapproximately equal to the inside diameter of the knife edge notch 64which is to be inserted therein. The depth of the groove 86 is madeapproximately equal to the thickness of the insulation of the wire to bestripped. The width of the groove 86 is made approximately equal to thethickness of the cutting knife 60 so that the cutting knife may beinserted into the groove, but, so that mold material will not flow intothe groove after insertion of the cutting knife therein. The outsidediameter of the groove 86 is located in relation to the collet mold 84of the mold insert 80 so that the stripper blade collets, such as 66, ofthe finished stripper blade, are properly located in relation to theknife edge notches 64 or 64'.

Although a mold insert and knockout pin 80 configured for use in moldingthe exemplary colleted stripper blade has been depicted and described,it should be understood that such knockout pin may be configured toproduce stripper blades having colletless cutting means.

In FIG. 5, a finished molded stripper blade 42 is shown being ejectedfrom the mold bottom 70 after the mold cover 72 has been separated fromsuch mold bottom, with such finished molded stripper blade being ejectedfrom such mold cavity by an upper knockout pin 82 and the collet moldinsert and knockout pin 80. Although a particular mold construction formolding the stripper blade of this invention has been described, itshould be understood that other mold designs having, for example,different mold parting lines, different positioning of centering andregistry pins could be used.

The stripper blade may also be formed by processes other than molding.What is important is to provide a laminated blade, or a blade formed ofa thin cutting knife of sheet material, which may be on the order of0.005 inch thick, embedded in a plastic or similar material. Joining ofthe laminates may be accomplished by bonding with an adhesive agent, orby other suitable means. For example, the blade 44 in FIG. 3, instead ofhaving a plastic molded about a thin cutting knife, may have a pair ofmatching laminates, for example plastic, bonded to opposite sides of theknife, to embed the knife in the blade structure.

The use, operation and function of this invention are as follows:

The stripper blade of this invention is utilized in stripping wire bymounting a pair of such blades, such as 42 and 44, in a stripper such asshown in FIG. 1. The blades are positioned and mounted so that thenotches and collcts arc symmetrically opposed and so that such bladesmay open and close relative to each other, with either both blades beingmovable or one blade fixed and one blade movable. The wire to bestripped is inserted between the open blades and the blades are closedabout the wire so that the exposed half moon area of the cutting knifeexisting between the knife edge notch and the collet severs the wireinsulation. The knife edge notch has a diameter slightly larger than thediameter of the inner metallic conductor of the wire to be stripped sothat as the opposed blades are closed, the inner metallic conductor ofthe wire to be stripped is not nicked. The collets, such as 66, areprovided to center the inner metallic conductor within the knife edgenotch as the blades are closed.

The method of this invention by which the stripper blade is fabricatedconsists of forming a metal insert or cutting knife; mounting suchcutting knife within a mold cavity; inserting mold material into themold cavity; and curing and ejecting the finished stripper blade fromsuch molded cavity.

The cutting knife 60 is formed by photoetching, stamping or other likesuitable process using thin sheet material approximately 0.005 inchthick. The cutting knife may be made using hardened spring steel, arigid plastic or other like material. The cutting edge may be carbide.In forming the cutting knife, registry holes are provided which alignthe cutting knife when the registry pins 78 of the mold bottom 70 areinserted through such holes. By using a thin cutting knife, the cuttingedge of such knife does not require sharpening. Although it has beenindicated that the cutting knife is approximately 0.005 inch thick andhas an unsharpened cutting edge, and such is the preferred form, itshould be understood that the cutting knife may be made of thickermaterial and may contain a sharpened single or double bevel cuttingedge.

The cutting knife 60 is positioned within the mold by extending thecollet mold an d knockout pin '80 out of the mold bottom 70, asgenerally shown in FIG. 5; placing the notched edge of the cutting knifeinto the groove 86 of the collet mold and knockout pin 80, therebypositioning the cutting knife notches relative to their respectivecollet molds; withdrawing such collet mold insert into the mold bottomuntil the mold bottom registry pins 78 are engaged in the cutting kniferegistry holes and the cutting knife abuts the mold bottom centeringpins 76; and placing the mold cover 72 upon the mold bottom, therebyvertically and laterally retaining the cutting knife within the moldcavity. With the cutting knife positioned and retained within the mold,mold material is inserted into the mold cavity, thereby forming thestripper blade body around the cutting knife.

The mold utilized in making the stripper blade of this inventioncontains a multifunction collet mold insert and knockout pin 80. Suchmold part may serve as a mold for the collets; contains a groove 86 intowhich the cutting knife 60 is inserted, thereby registering the cuttingedge notches with respect to the molded blade features; and serves as aknockout pin for use in ejecting the finished molded stripper blade fromthe mold bottom 70.

The collet mold insert and knockout pin 80 may be removed from the moldbottom 70 and replaced by a mold insert having differently configuredcollet molds or cutting means area mold, thereby permitting the moldbottom and cover 70 and 72 to be used in the production of variouslyconfigured stripper blades. For example, in producing a stripper bladefor use in stripping television antenna wire, a collet mold insert 80containing collet molds 84 which form collets conforming to televisionantenna wire would be inserted into the mold bottom 70, whereas, inproducing stripper blades for use in stripping circular wire, a colletmold insert 80 having semicircular collet molds 84 would be insertedinto the mold bottom 70.

By molding the stripper blade, special collet shapes for use instripping insulation from special wire shapes such as television antennawire and the like may be produced accurately and economically. Further,the collets maybe molded with knurled inner surfaces to provide improvedgripping action between the collets and the insulation to be removed.

The method of producing stripper blades disclosed herein results inuniform, accurate and interchangeable stripper blades. Therefore, shouldone blade of an operating pair of stripper blades become damaged, it isnecessary only to replace the damaged blade.

The stripper blade may be molded using plastic or other like moldablematerial such as metallic particles with graphite or other lubricatingmaterial dispensed therethrough. By using plastic or other moldableself-lubricating material, lubrication problems between the moving bladeand the wire stripper frame may be eliminated. Further, where thestripper blade design is such that either the insulation removed or leftintact must slide from within the collets when the blades are closed,plastic or other self-lubricating material will provide a good slidingsurface.

Another advantage of this invention is that it permits the economicaluse of a carbide-cutting edge on the stripper blade.

lclaim:

l. A blade structure for use in a wire stripper in stripping insulationfrom insulated wire, the blade structure including'a cutting knife inthe form of a thin metal laminate on the order of approximately 0.005 ofan inch thick embedded in a supporting structure, one edge of the metallaminate projecting beyond the supporting structure so as to expose acutting edge, at least one generally circular unsharpened notch

1. A blade structure for use in a wire stripper in stripping insulationfrom insulated wire, the blade structure including a cutting knife inthe form of a thin metal laminate on the order of approximately 0.005 ofan inch thick embedded in a supporting structure, one edge of the metallaminate projecting beyond the supporting structure so as to expose acutting edge, at least one generally circular unsharpened notch formedin the cutting edge of the laminate and being sized so as to generallyconform to but being slightly larger than the inner metallic conductorof the wire to be stripped, the portion of the supporting structureadjacent the cutting edge notch being shaped to conform to the notch butspaced from it.
 2. The structure of claim 1 further characterized inthat the supporting structure is comprised of fused metallic particles.3. The structure of claim 1 further characterized in that the Supportingstructure is made of nonmetallic plastic material.